Oral adhering discs, also called adhering troches, are known for time release of ingredients into saliva in the mouth or into the mucosa to which the disc is adhered or into mucosa that the disc touches while the disc is adhered to teeth or gums. Some oral adhering discs have two layers, a thin adhesive layer and a thicker, slowly dissolving ingredient release layer. Many synthetic hydrophilic compounds are known for use as the adhesive layer, such as poly-acrylic acid, carbomer, carbopol, and povidone. An effective natural compound, in sufficient concentration, is acacia gum, also known as gum arabic. As it dissolves in saliva, acacia gum adhesive is acidic, producing a local pH below 5.5, which is more acidic than desirable for contact with teeth.
Of course, the adhering objects need not be disc shaped. They may be squarish or oval or oblong or any other shape that is roughly flat at least on one side. A generic term that includes all such shapes is “adhering troche” (which a term for an object held in the mouth to achieve an effect).